|Statement||by L.E. Ramsahoye and S.M. Lang.|
|Series||Geological Survey water-supply paper -- 1536-C, Ground-water hydraulics|
|Contributions||Lang, S. M., New Jersey. Dept. of Conservation and Economic Development.|
|The Physical Object|
|Pagination||iii, p. 41-46 :|
|Number of Pages||46|
A SIMPLE METHOD FOR DETERMINING SPECIFIC YIELD FROM PUMPING TESTS, GROUND-WATER HYDRALICS [L.E.& Lang, S.M. Ramsahoye] on . Specific yield, applicable for The objectives of the pumping test are to determine well yie Introduction The basic concept of a pumping test is very simple water is removed by pumping Author: A. Balasubramanian. SPECIFIC YIELD COMPILATION OF SPECIFIC YIELDS FOR VARIOUS MATERIALS By A. I. JOHNSON ABSTRACT Specific yield is defined as the ratio of (1) the volume of water that a srturated rock or soil will yield by gravity to (2) the total volume of the rock or soil. Specific yield is usually expressed as a by: The principle of a pumping test is that if we pump water from a well and measure the discharge of the well and the drawdown in the well and in piezometers at known distances from the well, we can substitute these measurements into an appropriate well-flow equation and can calculate the hydraulic characteristics of the aquifer (Fig- ure ).
the well driller. Well yield tests are done using bailing1, air liftingor similar methods. Well yield tests are not as reliable as a pumping test in the following situations: Μ when well capacity is low (e.g., typical bedrock well); Μ when the maximum yield from the well is required; Μ when reliable estimates of aquifer properties are needed. pumping test data analysis which at present are exten sively used in analysis of problems involving Illinois wells. These methods are, the non-equilibrium "type curve" method, the modified non-equilibrium "straight line" method, the step-drawdown analysis developed . The Specific yield is dimensionless or can be given in %. 18 Specific capacity of a well: It is the ratio of discharge of the well to the drawdown, in m3 /hour/m. The objectives of the pumping test are to determine well yield, determine well efficiency, determine aquifer parameters and to examine water chemistry. Navigation: Pumping Test: Theory and Analysis Methods > Pumping Test Analysis Methods - Fixed Assumptions > Theis Recovery Test (confined) When the pump is shut down after a pumping test, the water level inside the pumping and observation wells will start to rise. This rise in water level is known as residual drawdown (s').
Methods of Pumping Test Specific Yield (Sy) is the volume of water yield by gravity drainage to the volume of the aquifer. The specific yield is dimensionless and typically ranges from to Duration of pumping test It’s difficult to determine how many hours that. the test, available drawdown, specific capacity, method of water level measurements and water levels/times recorded Well 2yield tests are done using bailing1 or air lifting methods. Well yield tests are not as reliable as a pumping test in the will design the pumping test and determine whether sentinel or observation wells (monitoring. Common types of pumping tests that you may perform include the following. Constant-rate tests maintain pumping at the control well at a constant rate. This is the most commonly used pumping test method for obtaining estimates of aquifer properties. Step-drawdown tests proceed through a sequence of constant-rate steps at the control well to determine well performance . All the other methods, however, are so complex that one needs a computer to apply them. We have also updated the book in the light of developments that have taken place since the first edition appeared some twenty years ago. We present, for instance, a more modern method of analyzing pumping tests in unconfined aquifers with delayed yield.